Telephone and telegraph switch-board



(No Model.) 3 Sheets-Sheet 1.

O. P. DANFORTH.

TELEPHONE AND TELEGRAPH SWITCH BOARD. No. 251,098. Patented Dec.20,1881.

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G. F. DANPORTH.

TELEPHONE AND TELEGRAPH SWITCH BOARD. No. 251,098. Patented Dec.20,1881.

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C.F.DANFORTH. 4 TELEPHONE AND TELEGRAPH SWITGH BOARD.

(No Model.)

Patented 'Dec. 20,1881.

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UNITE STATES PATENT O FrcE.

OHARLES F. DANFORTH, OF

CHELSEA, MASSACHUSETTS,

TELEPHONE AND TELEGRAPH SWITCH-BOARD.

SPECIFICATION forming part of Letters Patent No. 251,098, dated December20, 1881,

' Application filed May 18, 1881. (No model.)

To all whom it may concern: 4

Be it known that I, CHARLES FRANCIS DAN- FORTH, a citizen of the UnitedStates. residing at Chelsea, in the county of Sufi'olk and State ofMassachusetts, have invented a new and useful Improvement in TelephonicExchange Systems, of which the following is a specification.

My invention relates to a telephonic or telegraphic exchange system inwhich any one of the subscribers may be placed in communication with anyother one.

The object of my invention is to connect any one of a large number ofcircuits with any other. This has heretofore been accomplished inavariety of ways, some such system being in practical use in many placesin this country; but my improved system is whollyv new in oneparticular, and differs in many other minor respects from all othersknown to me.

The main novelty of my system resides in the use of a series ofconnecting-wires with each circuit-wire, as hereinafter more fullyexplained; and the minor features of my invention consist in thegrouping together of a number of circuit-wires with a correspondingnumber of connecting-wires,'as more fully explained below; and in themeans for connecting together any two of the connecting-wires, andthereby connecting together the two circuitwires which are connectedwith those connecting-wires.

In my improved s5 stem, as shown in the drawings and now to beexplained, each circuit-wire terminates in an insulated metalbar, andsixteen otherinsulated metal, bars are arranged about the circuit wirebar, so that either one of the sixteen can be readily connected to thecircuit-wire bar by a plug or other like eontrivan'ee, as will be wellunderstood by all skilled in this art. Sixteen connecting-wiresterminate each in one of these sixteen metal bars, the purpose being tomake it easy to connect the circuit-wire to either one of these sixteenconnecting-wires. (See the diagram Figure 7.) This series ofconnecting-wires so combiued with each circuitwire that the circuitwirecan be connected with either one of the connectingwircs is not only themain novelty of my invention, but is the main feature upon which mysystem is based. With this multiplicity ofconnecting-wires for eachcircuit-wire, it becomes easy to so arrange insulatedcrossing strips ofmetal, each a continuation of one of the connecting-wires, that any twoof these crossing strips may be readily connected, and as thecircuit-wire may be readily connected with either one of theconnecting-wires, it will be clear that all that is necessary to connecttogether any two circuit-wires will be to connect one of them with oneof the connectingwires and the other with another connectingwire andthen connect together these two connecting-wires by connecting thecrossing strips which are continuations'of these connectingwires. Onthis simple basis any number of circuit-wires can be practically managedby means of a device which is'not over-complicated, not likely to getout of order, and easily understood and used by operatives of averageskill.

I will now proceed to describe the preferred form of this device; but itwill be obvious that it is susceptible of numerous modifications,although in all the underlying principle must be the use of amultiplicity of connecting-wires for each circuit-wire.

In the drawings, Fig. 1 is a side View of one of the leaves, showing thearrangement of the subscribers wires A, connecting-wires B, drop-signalsO, and ground and battery wires D. Fig. 2 is a front view of either endof a leaf, showing the metallic plates 1) and d d, in which thehorizontal connecting-wires B and battery and ground wires D terminate,and the U-shaped metallic pieces E, in whichsubscriberswiresterminate,one wireto each piece. Fig. 3 is a section online 00 x, Figs. 1 and 2, showing the positions of the different wires.Fig. 4 is a front view of one side of a set ofleaves, the opposite sidebeing exactly the same. Fig. 5 is a section through one of theswitch-board s. Fig. dis a plan of one of the switch-boards. Fig. 7 is adiagram for illustration. Fig. 8 is a diagram showing the electricalconnections of theleaves with the switch-boards. Fig.9is an end view ofthe upper portion of one leaf and the lower portion of another, showingthe indicators, and section through two leaves, showing the manner ofmaking electrical connectionsat top or bottom with circuit andconnecting wires.

Each subscriber has a wire and a signaldrop, the drops being numberedand lettered as hereinafter stated. Each subscribers wire that is, eachcircuit-wire-inust be capable of ready connection with any one of anumber of connecting-wires-for example, as illustrated in the diagramFig. 7, where A represents a circuit-wire and B sixteenconnecting-wires, the circuit-wire terminating in a metal bar,E,and eachconnecting-wire in a metal bar, I). A number of such wires and drops (inthis instance sixteen of each) form a leaf, and a number of leaves (inthis instance sixty-eight) form a set, so that a set of leaves containsone thousand and eighty-eight circuit-wiresland drops, arranged insixteen rows, eight on each side and sixty-eight in 'each row. The rowsare lettered from A to H on one side and from I to P on the other. Theleaves are numbered from 1 to 68 on both ends, the same numbers being onthe opposite ends of the same leaf, and the ends of the leaves form thesides of a set. A subscriber is thus known by his row and number, as 17A57G, &c., on one side and 30K 19N, &c., on the other side. There willbean operator on each side of a set of leaves. The leaves are all exactlyalike, and a description of one will answer for all.

F is the frame, made of wood or other suitable material; A, thesubscribers wires, which may enter from top'or bottom, sixteen innumber, arranged on each side, near the signaldrops 0, in groups ofeight, four on each end, only being fully shown in Fig. l, but all ofthem in Fig 3. The connecting-\\'ires B are also sixteen in number, eachone extending from top to bottom and from side to side of the leaf, orconsisting of vertical and horizontal wires in metallic contact at theirpoints of crossing b. The connecting-wires terminate in metallicplates-b let into the frame F, and have their connections at the top andbottom of the frame F, as will be described farther on.

- The ground and battery wires D at each side are connected to metallicplates (1 (1, similar to those of the connecting-wires B.

E is a metallic U-shaped strip of metal let intothe frame F, out ofcontactwith the metallic plates 1), d, and d and wires B, but which canbe connected with either of the metallic plates 1) dd by a suitableplug.

When not in use each subscribers wire is connected to the ground-wirethrough the drop 0, strip E, and plug to plate d. It 1A desires tocommunicate, he completes the circuit, by any well known contrivance athis (ffiOE, through his drop 0, strip E, and plug, to plate 01, whichplate is connected with ground by ground-wire D. This causes his signalto drop and notify the operator, who removes the plug from d and plugsplated to strip E of 1A, thus connecting the battery which is connectedto plate 01 by wire D with the circuit-wire of 1A. The operator then,after having signaled 1A, removes the plug from plate d. He thenconnects strip E of 1A with his telephone and notifies 1A, who repliesConnect with 11?. The

operator then removes his telephone-plug and plugs lAs wire to anydisengaged connectingwire by plugging plate I) to strip E of 1A andnotifies the operator on the other side of the section, who rings up 1P,and on receiving an answer removes the plug from d of lPs strip E andplugs lPs strip. E to the plate I) corresponding to the plate I) towhich the wire of 1A is plugged, and completes the connection. Theconnection of a subscriber in one leaf with a subscriber in anotherleafis effected by means of the connecting-wires and switchboards, as Iwill now describe.

in the other, separated from each other, but

capable of being connected at their points of crossing by plugs. Theboard is divided into eight parts, each part containing one hundred andthirty-six strips-sixty-eight upper, c, and sixty-eight lower, a. Thestrips are numbered from 1 to 68in each part, so that there are an upperand lower strip in each part with the same number. For convenience inlocating, I make each part a separate board and number the boards from 1to 8, and place four on each side of the set of leaves, in reach of theoperators. The strips are designated by number, position, and number ofboard'as No. 1 upper str-ip in No. 1 board, No. 2 lower strip in No. 4board, &c. The sixteen connectingwires in each leaf are carried to theeight boards in the following manner, (see Fig. 8, in which the wiresfrom leaves 1, 2, and 68 are shown connected to their correspondingstrips in each of the eight boards 2) The two wires connected to the twoupper metallic plates 1) in each subscribers part in No. 1 leaf arecarried to the upper and lower No. l strip in No. 1 board. The twoconnected with the next lower metallic plates 1) in each subscriberspart in No. 1 leaf are carried to the upper and lower No. 1 strips inNo.2 board, from third pair of metallic plates 1) to No. 3 board, and soon for the eight pairs of metallic plates 2) in No. 1 leaf. The wiresthat connect with the right-hand metallic plates 1) are carried to theupper strips, 6, and those that connect with the lefthand metallicplates b to thelower strips, 0, in the switch-boards, reference beingbad always to the same end of the leaf. From No. 2 leaf they are carriedin the same manner to the upper and lower- No.2 strips in each of theeight boards, and so on for the sixty-eight leaves, so that each one ofthe sixteen connecting-wires from each of the sixty-eight -connectionsof the strips in the boards with connecting-wires from the differentleaves or groups must be made by plugs, so as to leave the strips freeto be connected with connectingwires from other similar sets whenrequired; and any two wires from different leavesone from each leafmaybe brought 'iuto electrical communication byjoining their correspondingstrips at any one of their points of crossing in any one of the boardsby a suitable plu v Various devices may be used for indicating at aglance what plates are disconnected, and consequently what strips in theswitchboards should be plugged together. A simple device is shown inFig. 9, in which the upper end of the eighth leaf and the lower end ofthe second leaf are shown with indicators for this purpose. All leaveshave the same at top and bottom, eight in each place. The top ones referto the upper strips, e, and the bottom ones to the lower strips, 0, inthe switch-boards, and the numbers show the number of the board. Woodenrods f extend through the leaf and project slightly at each end, andcarry suitable pins,f, the pins on each rod being in the same plane.Near each rod are numbers from 1 to 8, the same number being near eachend of the same rod, so that when the pin f on one end of a rod is madeto cover a number the pin on the other end covers a similar number. Whenthe operator on either side ofa set connects a plate, b, he immediatelycovers a corresponding number with a pin,f, thus cov ering a similarnumber and notifying the operator on the other side that such a platewith its connecting wire and strip in the switchboard is in use, forupper plates 1) covering 1, for next lower 2, for next 3, and so ononupper end for right side and on lower end for left side. The uncoverednumbers show the number of aboard in which a strip corresponding innumber to number of leaf on which the uncovered number is is not in use.

In Fig. 9 the upper part of No. 8 leat'shows 2, 3, and 5 uncovered,thusindicating that No. 8upper strips in Nos. 2, 3, and 5 boards are notin use. The lower part ofNo. 2 leaf shows 5, 6, and 8 uncovered, showingthat No. 2 lower strips in Nos. 5, 6, and S boards are not in use;

and thusit is known that No. Sleaf and No. 2

leaf can be connected in No.5 board. For instance, to connect 8A with2G, find in any one of the eight boards where a No. 8 strip, upper orlower, not in use crosses aNo. 2 strip, upper or lower, not in use,insert a plug at their point of crossing, anti connect the correspondingmetallic plate 1/ in SAs part to his wire and in 2Gs part to his wire.For instance, it the point of crossing should be in N0. 5 board, 8Aupper and 2G lower, the" right-hand metallic plate I) in fifth pair fromthe top in SAspart should be connected with his wire and the left-handmetallic plate I), fifth pair from the top in 2Gs part, connected withhis wire. Then the connection between SA and 2G will be established,through their circuit-wires, plates E, plugs, to metallic plates b,connecting-wires, and strips in theboard, and the line ready for use. Ifthe p tint of crossing should be in No. 8 board, 8A lower and 2G upper,the left hand lower or eighth row metallic plate I) in SAs part would beconnected to his wire, and the right-hand lower or eighth row metallicplate I) in 2 s part would be connected to his wire, and the connectioncompleted as above, and so on for any other board. Leaves andcorresponding strips can be added to a set to any desired extent; but Iprefer to make a separate set ofleaves and switch boards for, say, everyten hundred and eighty-eight wires.

Separate sets of leaves maybe connected by extending theconnecting-wires from one to the others and making the requisitecontacts by plugs; but I prefer to connect the opposite ends of thestripsin the boards by wires from .one set to another,and plugs so thatany board may be used by any one of a number of sets of sixty-eightleaves. The top and bottom of each leaf are notched, as shownin Figs. 2and 4. These notches fit into corresponding grooves in thesupporting-frame, so .that each leaf can be inserted or withdrawn, theelectrical contact being made, when the leaf is inits place, by metallicplates securedto the ends of each wire in the leaf and to the ends ofthe corresponding wires above or below, as shown in Fig. 9,"in whichmetallic plates 1 are shown attached to the wires in the leafandembedded in'the top and bottom pieces of the leafframe responding wires.

1 do not claim as my invention the method herein described forconnecting the subscribers wires in one group by means of the metallicplates 1), arranged adjacent to and for plugging connection with themetal bar E, as this may be accomplished in other ways, the object of myinvention being to provide a device for connecting the wires of onegroup with those of any'other, so that any subscriber in any one of thegroups may be put in communication with any disengaged SllbSCIlbt'li atany time, so that it may be possible for one half of the subscribers tocommunicate with the other halt at. the same time.

I claim as my invention and desire to secure by Letters Patent 1. In atelegraphic or telephonic exchange system in which the subscribers wiresare arranged in groups of equal number, the device above described forconnecting the wires of any one group with the wires of any other group,consisting of a switch board divided into half as many divisions orseparate boards as there are subscribers wires in one group,

each of these divisions or boards containing twice as many metallicstrips as there are groups, these strips being divided into twobinationof a number of groups of subscribers wires, annunciators, ground andbattery connections, and telephones with a switch board containing asmany metallic strips as there are subscribers wires in all the groups,each subscribers wire having plug-connection with two strips crossingeach other in different parts of the board half as many times as thereare subscribers wires in one group, these strips arranged to beelectrically connected at any of 20 their crossing points, substautially as described, and for the purposes set forth.

CHARLES FRANCIS DANFORTH. Witnesses:

OYRUs '1. CLARK, HENRY P. HALL.

